question Re: How can i remove registered host but do not added. in Support Questions

How can i remove registered host but do not added.

sam6315 — Tue, 23 Aug 2016 14:51:31 GMT

My cluster have registered hosts but do not added on cluster.

It means that,

I was installed ambari-agent on some hosts.

This hosts registered to ambari-server by changing server hostname on amber-agent.ini

But, I didn't registered on cluster using ambari web UI.

Some times later, when i was checked ambari-server log, ambari server still check this host's heartbeat.

"WARN [ambari-hearbeat-monitor] HeartbeatMonitor:154 - Heartbeat lost from host hostname"

how can i remove this hosts?

Re: How can i remove registered host but do not added.

ssharma — Tue, 23 Aug 2016 14:58:10 GMT

host-list.jpeg host-details.jpeg@James Lee

Do you see these unwanted hosts under 'hosts' tab in ambari?

Then click on that particular host's page and goto host details page. From the 'hosts action' dropdown, delete the host.

Attaching the screenshots.

Re: How can i remove registered host but do not added.

sam6315 — Tue, 23 Aug 2016 15:11:26 GMT

I don't add on Ambari web ui. So, I can't see anywhere.

But, ambari-server still check heartbeat.

When i try to add host, on Confirm hosts tab, i can see this hosts on 'Other Registered Hosts' menu.

This menu say that, "These are the hosts that have registered with the server, but do not appear in the list of hosts that you are adding."

Re: How can i remove registered host but do not added.

sshimpi — Tue, 23 Aug 2016 15:29:17 GMT

@James Lee

To remove the host from the cluster follow below steps -

1. Stop the ambari-agent on the node. you want to remove.

2. Remove the ambari-agent packages from that node using $yum remove ambari-agent

3. On safer side you can run $hdfs dfsadmin -refreshNamenodes command to refresh nodes on cluster

4. Confirm using $hdfs dfsadmin -report the host is no more part of cluster.

Re: How can i remove registered host but do not added.

sam6315 — Tue, 23 Aug 2016 16:04:52 GMT

"hdfs dfsadmin -report" command is not shown registered but don't added hosts.

refreshNamenodes datanodehost:port

For the given datanode, reloads the configuration files, stops serving the removed block-pools and starts serving new block-pools.

refreshNodes

Re-read the hosts and exclude files to update the set of Datanodes that are allowed to connect to the Namenode and those that should be decommissioned or recommissioned.

I think refreshNamenodes command is not correct in my problem, so i try to refreshNodes command, but it doesn't works. Ambari-server still write heartbeat lost log.

Re: How can i remove registered host but do not added.

sam6315 — Tue, 23 Aug 2016 16:14:04 GMT

I was found this hosts ambari.hosts and ambari.hoststate on postgre database.

This host's health_status is UNKNOWN.

I want to remove this hosts clearly.

Re: How can i remove registered host but do not added.

Former Member — Tue, 23 Aug 2016 16:47:24 GMT

Ideally on every restart of ambari agent it sends a registration request to the ambari server along with it's latest (Hostname+IPAddress). That is then stored in the "hosts" table of ambari DB.

You can check the hostnames that are registered using the curl command as following:

curl -i -H "X-Requested-By: ambari"-u admin:admin -X GET http://localhost:8080/api/v1/hosts

If you find that the hostnames are not correctly set/updated then may be you can take a look at the following article to check the public_hostname / hostname:

https://community.hortonworks.com/content/kbentry/42872/why-ambari-host-might-have-different-public-host-n.html

So if you do not want to incorrect agent to be registered then uninstall that agent and do not restart it back.

Re: How can i remove registered host but do not added.

sganatra — Tue, 23 Aug 2016 18:37:02 GMT

You have a "hoststate" and/or "hosts" table in ambari database which might have an entry of that hostsname which will give you that WARN [ambari-hearbeat-monitor] HeartbeatMonitor:154 - Heartbeat lost from host hostname" on every ambari-server restart is performed as it checks those tables. You might want to have a check if the entry exists then remove those entries by stopping the ambari-server and stopping the ambari-agent of those host which gives you that warning.

Because if the ambari-agent is in running state then you will see the same issue again.

Re: How can i remove registered host but do not added.

sganatra — Tue, 23 Aug 2016 19:01:59 GMT

You could remove via delete statement in psql..

1) Removing table entries in hoststate : Delete from hoststate where host_id=xx

2) Removing table entries from hosts : Delete from hosts where host_id=xx

And restart ambari-server

Re: How can i remove registered host but do not added.

sam6315 — Wed, 24 Aug 2016 07:16:56 GMT

You could remove via delete statement in psql..

1) Removing table entries in hoststate : Delete from hoststate where host_id=xx

2) Removing table entries from hosts : Delete from hosts where host_id=xx

And restart ambari-server

thx. It works.

Re: How can i remove registered host but do not added.

sam6315 — Wed, 24 Aug 2016 07:45:19 GMT

This curl command shown registered hosts. thx!

I try to below command, it works.

curl -i -H "X-Requested-By: ambari"-u admin:admin -X DELETE http://localhost:8080/api/v1/hosts/hotname

Re: How can i remove registered host but do not added.

dpnctl — Mon, 02 Jan 2017 16:22:18 GMT

I restarted the ambari-agent services and was able to reregister we also have an option of ambari-agent reset hdp_server_name this was also required on other 2 hosts

Re: How can i remove registered host but do not added.

ramu_valleti — Thu, 22 Feb 2018 16:54:57 GMT

Above curl command worked in my case. Thanks.